The head structure of a brush appliance is of crucial importance for the cleaning effect and other extended functions of the brush. Therefore, a variety of improvements have been made to the head structure of brush appliance.
US2010/0036656A1 discloses a brush part of an electric toothbrush, which has a head and comprises a frame, a movable contact element retainer, and an extension part of the movable contact element retainer. The frame comprises a plurality of first contact elements supported in it. The movable contact element retainer comprises a plurality of second contact elements supported in it, and is configured to receive the energy for cleaning movement from an electric driver, such that it has at least one free movement in relation to the first contact elements. The extension part of the movable contact element retainer is arranged on the top of the head, with clearance between the extension part and the frame, wherein, the width of at least a first part of the clearance in the side edge area of the head part is smaller than the width of a second part of the clearance in the inner area of the head.